I. Field of the Invention
The present invention relates to sunscreen. More particularly, the present invention relates to sunscreen that are applied as a lotion or as a spray.
II. Description of the Prior Art
Sunscreen compositions are applied to the skin to protect the skin from the sun""s ultraviolet rays that can lead to erythema, a reddening of the skin also known as sunburn. Sunlight or ultraviolet radiation in the UV-B range has a wavelength of 290 nm to 320 nm and is known to be the primary cause of sunburn. Ultraviolet rays at a wavelength of 320 nm to 400 nm, known as UV-A radiation, produces tanning of the skin. However, in the process of doing so, the UV-A rays can damage or harm the skin.
Besides the immediate malady of sunburn, excessive sunlight exposure can lead to skin disorders. For instance, prolonged and constant exposure to the sun may lead to actinic keratoses and carcinomas. Another long-term effect is premature aging of the skin. This condition is characterized by skin that is wrinkled, cracked and has lost its elasticity.
As stated above, sunscreens are typically formulated with the goal of inhibiting skin damage from the sun""s rays. The sunscreen composition filters or blocks the harmful UV-A and UV-B rays that can damage and harm the skin. It is believed that sunscreen agents accomplish this by absorbing the UV-A and/or UV-B rays.
In general, sunscreen compositions are oil in water emulsions. In this system, the UV-absorbing compounds are typically incorporated into the oil phase.
Consumers consider many factors when purchasing a sunscreen product. One of the most important considerations is the sun protection factor (SPF). This determines the amount of protection that the sunscreen composition provides over a given period of time. There are many to choose from and selection will be based upon the consumer""s needs. The consumer also gives consideration to the substantivity of the product, that is how durable is the product after applying it over the skin. This affects how often the composition will need to be applied when the consumer is out in the sun. A third consideration is product feel and how well the product spreads over the skin. Typically, consumers want a product that feels smooth and silky and can be applied in a smooth, continuous film over the skin. Another factor is the shelf life of the product, which is determined by the chemical and physical stability of the sunscreen composition. In addition, product form will also play a part since there is a variety of choices such as lotions, gels, creams, and sprays which are available. Form preference could ultimately determine whether the consumer decides to purchase the product.
Most sunscreen compositions are formulated for use as a lotion. The consumer would squeeze the lotion out of the package and rub the sunscreen composition over the skin. However, the use of sunscreens in a spray form is gaining popularity. But, a formulation made to be applied as a lotion cannot be used in a spray vehicle without modification and reformulation. This requires product reformulation, which requires time and money.
A composition that is capable of functioning as a lotion or a spray is desirable. This would save time in formulation development costs and would improve manufacturing efficiencies. For instance, the same raw materials would be used in the lotion and spray, thus potentially reducing raw material and storage costs.
It is an object of the present invention to provide a sunscreen composition that can be effectively applied as a lotion.
It is also an object of the present invention to provide such a sunscreen composition that can also be effectively applied as a spray.
It is another object of the present invention to provide such a sunscreen composition that either as a lotion or spray spreads uniformly over the skin.
It is yet another object of the present invention to provide such a sunscreen composition that reduces viscosity as it is sheared in order that the composition may be used as a lotion or a spray.
To accomplish the foregoing objects and advantages, the present invention, in brief summary, is a sunscreen composition that can conveniently be used as a lotion or a spray, without any change to the composition. The composition has a sunscreen agent, a rheological additive, a pH adjuster, and water. In a preferred embodiment, the sunscreen composition also contains an emulsifier, an emollient, a moistening agent, a waterproofing agent, and/or a preservative.